In copending applications entitled "Railway Hopper Car", Ser No. 473,371, filed Mar. 8, 1983, which is a continuation of application Ser. No. 236,861, filed Feb. 23, 1981, now abandoned and "A Low Level Freight Car for Carrying Trailers", Ser No. 434,294, filed Oct. 14, 1982, which is a continuation of application Ser. No. 147,965, filed May 8, 1980, now abandoned, both of which are assigned to the same assignee as the present invention, there is described a hopper car in which a pair of adjacent units of the car are connected by a single truck. A coupler between the units and the truck provide articulation therebetween. The coupler includes conventional male and female connector elements connected to the same center pin to permit the adjacent units to swivel about a common point on the truck. The coupler assists in inhibiting rock and roll movement and reduces slack run out between the units.
The articulated units using a coupler of the type mentioned in the aforementioned application has some effect in reducing the curving forces on the wheels during curves. However, when left to the coupler alone, the arrangement sometimes results in a high angle of attack between the lead outer wheel and the rail. This causes wheel wear and has other undesirable results.
The use of forced steering to reduce wheel flange wear, rail gauge wear, wheel/rail noise and energy consumption when a rail car is negotiating a turn is known. One such forced steering system is described in a copending application entitled "An Articulated Truck Assembly", Ser. No. 306,156, filed Sept. 28, 1981, also assigned to the same assignee as the present invention.
It is desirable to provide an articulated truck designed to join and support adjacent rail cars or units while still offering the advantages of forced steering for the truck.